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Coma - definitie

Coma - definitie. Insuficienta cerebrala acuta Absenta constientei de sine sau a mediului inconjurator Nu deschide ochii, nu vorbeste, nu raspunde la comenzi. Fiziopatologie.

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Coma - definitie

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  1. Coma - definitie • Insuficienta cerebrala acuta • Absenta constientei de sine sau a mediului inconjurator • Nu deschide ochii, nu vorbeste, nu raspunde la comenzi

  2. Fiziopatologie • Leziuni la nivelul sistemului reticulat activator din trunchiul cerebral fie leziuni la nivelul cortexului (lez. anatomice structurale) • Alterarea proceselor metabolice cerebrale (coma metabolica) – alterarea substratului energetic, modificarea potentialelor de repaus ale membranelor neuronale, anormalitati ale neurotransmitatorilor

  3. Neuroanatomie simplificata • Trezirea : unde este localizata? • Sistemul reticulat activator ascendent ‘miezul trunchiului cerebral’ • Input de la numeroase aferente somatice • Output catre nucleii talamici (sunt in circuit cu structurile corticale) si sistemul limbic

  4. Sistemul reticulat activator ascendent • Este o poarta, ce creste sau scade influentele inhibitaorii ale talamusului asupra cortexului cerebral • Modifica efectele stimulilor senzoriali ascendenti • Modifica stimulii corticali descendenti

  5. Gravitatea depinde de profunzimea si de durata ei • Coma nu este o stare permanenta – pacientii fie se trezesc, fie raman cu diferite grade de disfunctie nervos centrala • “Coma cronica” = stare vegetativa persistenta

  6. Evaluarea comei – scara Glasgow • Permite o examinare neurologica simpla si reproductibila • Evaluare rapida a starii neurologice • Urmarirea in dinamica a evolutiei neurologice in timp • Compararea la mai multe examinarii sau de mai multi examinatori

  7. Scor Glasgow <8 = leziuni cerebrale grave

  8. Diagnostic diferential • Sindrom de “locked in” • Areactivitate psihogena • Mutism akinetic • Moarte cerebrala

  9. Mutism akinetic • Pacient silentios (mutism), imobil (akinetic) dar vigil • Datorat unor leziuni bilaterale la nivelul lobilor frontali sau leziuni bilaterale talamice • Ex: boala Creutzfeld-Jakob

  10. Catatonia • Simptom complex asociat unor boli psihice grave: • stupor, mutism, modificari posturale • Poate fi intalnita si in unele suferinte cerebrale organice : encefalita, psihoza toxica sau indusa medicamentos

  11. Sindromul “Locked-In” • Infarct pontin (afectate toate fibrele motorii descendente) • Poate cruta miscarea ochilor • Poate cruta deschiderea ochilor • EEG normal sau cu activitate alfa

  12. Sindromul Locked-in Infarct Pontin

  13. “Amintirile unui mort despre viata” Carte publicata in 1997 de un ziarist francez care a avut un atac cerebral urmat de sindromul de “locked in”

  14. Cauze • Neurologice • Traumatisme craniocerebrale • Accidente vasculare cerebrale • Tumori • Metabolice • Hipo/hiperglicemie • Hiposodemie • Encefalopatie hepatica • Endocrine • Panhipopituitarism • mixedem • Toxice

  15. Hematom subdural

  16. Hematom epidural

  17. Abces cerebral

  18. Evaluare • Ancheta (contextul instalarii comei) • + evolutia tulburarilor de constienta • Examen clinic initial • Functii vitale • Neurologic

  19. Indicii din istoric • Instalarea simptomelor • Instalare brusca • Prodrom, fluctuatii • Siptome neurologice asociate preexistente • Medicatie cronica

  20. Obiective terapeutice • A – libertatea cailor aeriene • B – asigurarea respiratiei • C – asigurarea circulatiei • Tratamentul prompt al cauzelor metabolice cu risc vital imediat (hipoglicemia) • Evaluarea riscului unei presiunii intracraniene crescute si masuri terapeutice imediate

  21. Bilant biologic • Glicemie • Ionograma • Gaze sanguine • Ex. toxicologic • Explorari paraclinice • CT • Punctie lombara

  22. Coma postresuscitare • Numai 25-50% din cei resuscitati parasesc spitalul! • In mod evident daca nu resuscitam nu va exista supravietuire, dar daca nu paraseste spitalul nu exista castig real

  23. De ce mor pacientii? • Circa 1/3 leziuni SNC • Circa 1/3 leziuni miocardice • Circa 1/3 din alte cauze: infectii etc… Schoenenberger et al. Arch Intern Med 1992;154:2433

  24. Cerebral Performance Categorie Good Cerebral Performance : Conscious. Alert, able to work and lead a normal life. May have minor psychological or neurological deficits (mild dysphasia, nonincapacitating hemiparesis, or minor cranial nerve abnormalities). 1 Moderate Cerebral Disability : Conscious. Sufficent cerebral function for part-time work in sheltered environment or independent activities of daily life (dressing, traveling by public transportation, and preparing food). May have hemiplegia, seizures, ataxia, dysarthria, dysphasia or permanent memory or mental changes. 2 Severe Cerebral Disability. Conscious. Dependent on others for daily support because of impaired brain function (in an institution or at home with exceptional familiy effort). At least limited cognition. Includes a wide range of cerebral abnormalities from ambulatory with severe memory disturbance or dementia precluding independent existence to paralytic and able to communicate only with eyes, as in locked-in-syndrome. 3 Coma, vegetative state. Not conscious. Unaware of surroundings, no cognition. No verbal or psychological interactions with environment. 4 Death. Certified brain dead or dead by traditional criteria. 5

  25. The Use of Hypothermia After Cardiac Arrest Benson DW, Williams GR Jr, Spencer FC, Yates AJ.Anesth Analg 1959; 38: 423-8. • Comatose survivors • Asystole or VF • 31-32°C • Cooling until neurologic recovery(3 hours to 8 days) • Water-filled blanket

  26. Mild Therapeutic Hypothermia to Improve the Neurologic Outcome After Cardiac Arrest (HACA) • Patients with witnessed cardiac arrest from VF or pulseless VT, 18-75 years of age, estimated 5-15 minutes to attempted resuscitation, and less than 60 minutes from collapse to restoration of spontaneous circulation • 275 patients of 3,551 cardiac arrests studied (8%) • 137 patients received hypothermia Dr. Fritz Sterz, Vienna, Austria, and The Hypothermia After Cardiac Arrest Study Group, N Engl J Med 2002; 346:549-556

  27. Hypothermia for Coma After Cardiac Arrest Hypothermia Normothermia Dr. Fritz Sterz, Vienna, Austria and The Hypothermia After Cardiac Arrest Study Group, N Engl J Med 2002; 346:549-556

  28. Junko Suzuki Machida City Museum Tokyo “Cuget, deci exist.”Rene Descartes

  29. Ce este moartea si cum se poate defini? Care sunt semnele mortii?

  30. ISTORIC • <1627 moarte = absenta respiratiei • >1627 (W.Harvey) moarte = absenta • reactivitatii • respiratiei • batailor inimii • Moses Maimonides (1135-1204) nascut in Cordoba; rabin, filozof si medic care constata ca unui decapitat pentru cateva zeci de secunde ii mai bate inima

  31. 1959 Mollaret si Goulon publica in Revue Neurologique “le coma depasse” absenta respiratiei spontane (suport ventilator) absenta reflexelor de trunchi colaps circulator 1968 criteriile Harvard 1956 Lofstedt si von Reis - 6 pacienti ventilati cu absenta reflexelor de trunchi, hipotermie si poliurie - la autopsie au necroza cerebrala 1959 Wertheimer, Jouvet si Descotes vorbesc de moartea sistemului nervos ISTORIC

  32. CRITERIILE HARVARD DE MOARTE CEREBRALA • Areactivitate • Absenta miscarilor spontane • Absenta respiratiei spontane • Areflectivitate • EEG cu traseu isoelectric cele de mai sus se reevalueaza la 24 ore se exclude hipotermia sau depresoarele SNC • concluziile Raportului Comitetului Ad Hoc al Universitatii de Medicina Harvard Beecher H.W. JAMA 205:337-340 1968

  33. CRITERIILE MINESOTA (1971) • leziune cerebrala cunoscuta si ireversibila • eliminarea factorilor metabolici • absenta miscarilor spontane • apnee (4min) • absenta reflexelor de trunchi: fotomotor, cornean, oculovestibular, deglutitie • persistenta tuturor elementelor dupa 12 ore la reevaluare

  34. CODUL MARII BRITANII (1976) • coma profunda • fara medicamente depresoare • fara hipotermie • fara modificari metabolice remediabile • ventilatie spontana absenta • fara medicamente depresoare sau curare • cauza determinata de leziuni cerebrale ireversibile • teste diagnostice • absenta reflexului fotomotor, cornean, oculovestibular • stimularea periferica nu genereaza raspuns motor mediat central • absenta deglutitiei sau reflexului de tuse • absenta miscarilor respiratorii la indepartarea ventilatorului si cresterea PaCO2 mai mare de 50mmHg

  35. CRITERIILE SOCIETATII AMERICANE DE NEUROLOGIE (1995) • demonstrare comei • evidentierea cauzei • absenta factorilor de interferenta: hipotermie, medicamente, modificari metabolice sau electrolitice • absenta reflexelor de trunchi • absenta raspunsului motor • apnee • reevaluare la 6 ore dar intervalul de timp este considerat arbitrar • teste confirmatorii de lab. sunt necesare numai daca componente specifice ale testelor clinice nu pot fi evaluate cert

  36. MOARTE CEREBRALA = Pierderea definitiva a tuturor functiilor neuronale integrative, moartea intregului creier, inclusiv a trunchiului cerebral

  37. MECANISMUL MORTII CEREBRALE reabsorbtie LCR PIC trauma hipoxie ischemie hemoragie tumora toxicitate herniere efect de masa edem insuficienta resp congestie venoasa ischemie arteriala oprire circulatorie Autoliza creier Silentium EEG Leestma, Brain Death, 2001

  38. Angiografie cerebrala normala Angiografie cerebrala in moarte cerebrala

  39. STABILIRE A DIAGNOSTICULUI DE MOARTE CEREBRALA • cauza neurologica clara si ireversibila • absenta functiei neurologice • apneea • teste aditionale confirmatorii

  40. IREVERSIBILITATEA excluderea cauzelor reversibile: hipotermie, soc, tulb. metab. endocrine, droguri cauza neurologica absenta ameliorarii la 6 ore

  41. ABSENTA FUNCTIEI NEUROLOGICE incetarea functiei intregului creier, inclusiv a trunchiului cerebral - coma profunda, areactiva - pupile fixe, areactive - absenta reflex. de trunchi cerebral

  42. Anatomia creierului Cortex Cerebral Sistem Reticulat Activator Trunchi cerebral

  43. Trunchi cerebral mezencefal Nerv cranian III • reflex pupilar • miscarea ochilor

  44. Trunchi cerebral • Punte • nervi cranieni IV, V, VI • miscari conjugate globi oculari • reflex cornean

  45. Trunchi cerebral • bulb nervi cranieni IX, X • reflex de inghitire • reflex de tuse • Respiration

  46. APNEEA(TEST DE APNEE) • absenta miscarilor respiratorii dupa deconectarea de ventilator pina la PaCO2 = 60 mm Hg • prealabila ventilatie 10 min cu O2 100% • administrare de O2 100% pe sonda IOT • sub controlul SpO2 Anexa la Legea privind prelevarea si transplantul detesuturi si organe umane Monitorul Oficial, ianuarie 1998

  47. TESTE DE CONFIRMARE • EEG • potentiale evocate • Doppler transcranial • scintigrafie • angiografie cerebrala

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